Distributed algorithms for multicast path setup in data networks

Establishing a multicast tree in a point-to-point network of switch nodes, such as a wide-area asynchronous transfer mode (ATM) network, can be modeled as the NP-complete Steiner problem in networks. In this paper, we introduce and evaluate two distributed algorithms for finding multicast trees in point-to-point data networks. These algorithms are based on the centralized Steiner heuristics, the shortest path heuristic (SPH) and the Kruskal-based shortest path heuristic (K-SPH), and have the advantage that only the multicast members and nodes in the neighborhood of the multicast tree need to participate in the execution of the algorithm. We compare our algorithms by simulation against a baseline algorithm, the pruned minimum spanning-tree heuristic that is the basis of many previously published algorithms for finding multicast trees. Our results show that the competitiveness (the ratio of the sum of the heuristic tree's edge weights to that of the best solution found) of both of our algorithms was, on the average, 25% better in comparison to that of the pruned spanning-tree approach. In addition, the competitiveness of our algorithms was, in almost all cases, within 10% of the best solution found by any of the Steiner heuristics considered, including both centralized and distributed algorithms. Limiting the execution of the algorithm to a subset of the nodes in the network results in an increase in convergence time over the pruned spanning-tree approach, but this overhead can be reduced by careful implementation     

LabVIEW嵌入式技术：嵌入式设计需求的迁移

很多因素导致设计的复杂性增加，而且这种增长趋势还在继续。10年前，一个嵌入式系统平均只有100000行代码。到2001年，这个数字超过了100万，到今天，甚至远远超过500万。由于硅芯片变得越来越经济高效，开发人员正在转向32位微处理器单元（MPU）。市场研究公司Venture Development Corporation（VDC）的一项调查显示，在今后两年将有61％的被调查者采用32位MPU，因为硬件成本不再是决定性的因素。此外，嵌入式设计的需求在很多不同的应用领域都在增长。例如，多媒体正在促进更多面向数字信号处理系统的应用；汽车通信系统需要高性能的处理能力；工业机器和传感器需要嵌入式控制，这些需求使工程师和科学家，或领域专家，或非典型DSP开发人员，寻求不同的方法来对嵌入式系统编程。随着这些不断增长的复杂性，传统的嵌入式系统的开发方法已经不能满足需求。例如，基于文本的面向对象的设计工具不能提供有效的建模方法，尤其是在有时间和并行性要求的时候。     

Rate-proportional servers: a design methodology for fair queueingalgorithms

Generalized processor sharing (GPS) has been considered as an ideal scheduling discipline based on its end-to-end delay bounds and fairness properties. Until recently, emulation of GPS in a packet server has been regarded as the ideal means of designing a packet-level scheduling algorithm to obtain low delay bounds and bounded unfairness. Strict emulation of GPS, as required in the weighted fair queueing (WFQ) scheduler, however, incurs a time-complexity of O(N) where N is the number of sessions sharing the link. Efforts in the past to simplify the implementation of WFQ, such as self-clocked fair queueing (SCFQ), have resulted in degrading its isolation properties, thus affecting the delay bound. We present a methodology for the design of scheduling algorithms that provide the same end-to-end delay bound as that of WFQ and bounded unfairness without the complexity of GPS emulation. The resulting class of algorithms, called rate-proportional servers (RPSs), are based on isolating scheduler properties that give rise to ideal delay and fairness behavior. Network designers can use this methodology to construct efficient fair-queueing algorithms, balancing their fairness with implementation complexity     

Solutionizing effects on deformation-induced phase transformations in 2014 aluminum composite

A solutionizing heat treatment of 2014 aluminum alloy reinforced with 0.15 volume fraction of alumina particles (VFAP) results in deformation-induced precipitation during rolling and tensile deformation, with 0.10 VFAP, at room temperature. The extent of precipitation increases with increase in time and/or temperature of solutionizing. An attempt has been made to identify the various types of precipitates in the samples deformed to a given strain and in fractured conditions. The work-hardening curves and tensile properties of the composites have been shown to be dependent on the time and temperature combination of the solutionizing process.     

Enhanced specificity of truncated transmembrane protein for serologic confirmation of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 infections by western blot (immunoblot) assay containing recombinant envelope glycoproteins

Immunoassays based on the highly immunogenic transmembrane protein of human T-cell lymphotropic virus type 1 (HTLV-1) (protein 21c) are capable of detecting antibodies in all individuals infected with HTLV-1 and HTLV-2. However, because of antigenic mimicry with other cellular and viral proteins, such assays also have a large proportion of false-positive reactions. We have recently identified an immunodominant epitope, designated GD21-I located within amino acids 361 to 404 of the transmembrane protein, that appears to eliminate such false positivity. This recombinant GD21-I protein was used in conjunction with additional recombinant HTLV type-specific proteins and a whole virus lysate to develop a modified Western blot (immunoblot) assay (HTLV WB 2.4). The sensitivity and specificity of this assay were evaluated with 352 specimens whose infection status was determined by PCR assay for the presence or absence of HTLV-1/2 proviral sequences. All HTLV-1-positive (n = 102) and HTLV-2-positive (n = 107) specimens reacted with GD21-1 in the HTLV WB 2.4 assay, yielding a test sensitivity of 100%. Furthermore, all specimens derived from individuals infected with different viral subtypes of HTLV-1 (Cosmopolitan, Japanese, and Melanesian) and HTLV-2 (IIa0, a3, a4, IIb1, b4, and b5) reacted with GD21-I in the HTLV WB 2.4 assay. More importantly, HTLV WB 2.4 analysis of 81 PCR-negative specimens, all of which reacted to recombinant protein 21e in the presence or absence of p24 and p19 reactivity in the standard WB assay, showed that only two specimens retained reactivity to GD21-I, yielding an improved test specificity for the transmembrane protein of 97.5%. None of 41 specimens with gag reactivity only or 21 HTLV-negative specimens demonstrated reactivity to GD21-I. In an analysis of additional specimens (n = 169) from different geographic areas for which PCR results were not available, a substantial increase in the specificity of GD21-I detection was demonstrated, with no effect on the sensitivity of GD21-I detection among specimens from seropositive donors. Thus, the highly sensitive, GD21-I-based HTLV WB 2.4 assay eliminates the majority of false-positive transmembrane results, thereby increasing the specificity for serologic confirmation of HTLV-1 and HTLV-2 infections.     

Raman scattering and SEM studies of graphite and silicon carbide surfaces bombarded with energetic protons,deuterons and helium ions

Experimental investigations on the chemical and physical effects of 10–15 keV H₁⁺, D₁⁺ and He⁺ ion bombardments to fluences up to 10¹⁹ ions/cm² on graphite and SiC have been conducted using the techniques of Raman scattering and scanning electron microscopy (SEM). Raman scattering data for ion bombarded graphite reveal the formation of an amorphous surface layer as indicated by the appearance of a broad band in the spectrum centered at 1525 cm which replaces the bands due to microcrystalline carbon at 1585 cm^?1 and 1360 cm^?1. The microcrystalline structure could be partially restored upon vacuum annealing at 1040°C for several hours. A weak, broad band centered at 2150 cm also appears after bombardment which is indicative of the formation of ?C = C? bonds. Surfaces of “KT” SiC were also amorphized on ion bombardment as indicated by changes in the Raman spectra. Chemical trapping of the incident h₁⁺ and D₁⁺ ions to form bulk C-H, C-D and Si-H species was observed. Preferential sputtering of Si leaving a carbon rich surface region also occurred. Blister formation was observed in the SEM studies.     

可双向通信的智能电子插座_Vidyut

位于印度卡纳塔卡邦班加罗尔的Indrion技术公司认为公司的使命是：通过在应用中嵌入无线传感器-作动器控制网络（WSN）的智能,实现能感知情境的生态系统,从而提高生活质量。Indrion公司通过嵌入WSN技术的自适应、标准未知、情境感知、可缩放的平台Indriya^TM与Kriya^TM,实现了高能效和高运行效率,并整合嵌入软件、分析方法、控制算法、用户界面,实现了一系列面向应用的解决方案。